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OCR A Level Chemistry A – Module 6 Organic Chemistry and Analysis

6.1.2
Carbonyl
Compounds

Section 6.1.2 covers the reactions of carbonyl compounds: oxidation of aldehydes with acidified dichromate(VI), nucleophilic addition of NaBH₄ and of HCN (NaCN(aq)/H⁺(aq)) with their mechanisms, and the characteristic tests: 2,4-dinitrophenylhydrazine to detect and identify a carbonyl compound, and Tollens’ reagent to detect an aldehyde.

Exam Paper
Paper 2 & 3
H432/02 and H432/03
Learning Outcomes
6.1.2 (a) – (e)
5 learning outcomes
Sub-topics
3 lessons
Revision notes available
Exam Board
OCR
H432 (2015 onwards)

Revision Notes

3 revision notes, in the order the specification teaches them.

An aldehyde beside a ketone with their C=O groups picked out
1

Aldehydes and Ketones: Structure, Naming and Properties

Aldehydes and ketones: functional groups, nomenclature and formulae, the polar carbonyl group, boiling points and solubility in water.

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A carbonyl molecule and a silver mirror test
2

Oxidation and Tests for Carbonyl Compounds

Oxidation and tests for aldehydes and ketones: Tollens’ reagent, acidified dichromate(VI), 2,4-DNPH.

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A nucleophile adding to a carbon-oxygen double bond
3

Reduction and Nucleophilic Addition of Carbonyl Compounds

Carbonyl reduction with NaBH₄ and nucleophilic addition of HCN: equations, the mechanism and the formation of hydroxynitriles.

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Summary Map

Download, print and revise the reactions of this topic at a glance.

Summary maps

Download, print and revise the reactions of this topic at a glance.

Illustration of a summary map: compounds joined by reaction arrows
Summary map · PDF

Aldehydes and Ketones Map

OCR A Level Chemistry A · 6.1.2 Carbonyl compounds

Every reaction on one A4 page: reagents, conditions and reaction type for each arrow, colour coded, with the key tests.

Download the map3 reactions · A4 portrait · print ready
Illustration of a summary map: compounds joined by reaction arrows
Summary map · PDF

Carbonyl Compounds Summary Map

OCR A Level Chemistry A · 6.1.2 Carbonyl compounds

The whole section on one A4 page: oxidising aldehydes, telling them apart, reduction with NaBH₄, the mechanism, NaCN with acid, and 2,4-DNP.

Download the map6 key ideas + a data table · A4 portrait · print ready

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Revision Game

Match reagents to products, free, with your board's reagents and conditions.

Illustration of memory game cards, two turned face up as a matching pairFree

Revision Game: Aldehydes and ketones

Turn the cards over two at a time: match reagents to what they make, and find how each product is made.

A free memory game on the reactions in this topic, with your board's reagents, conditions and spec points.

  • Two ways to playMatch each set of reagents to what the reaction makes, or see a product and find the reactant and reagents that make it.
  • Drawn the way the exam draws themEvery structure is drawn in ChemDraw, with the reagents and conditions your exam board asks for.
  • It countsRounds earn XP and keep your streak going, and every correct match shows in your KASP analytics, apart from your marks.

Study Cards

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Specification

Every specification point in this topic, in the exam board's own words. Rate how confident you are with each one.

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Self-assessment · 9 points

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6.1.2

  1. a

    oxidation of aldehydes using Cr2O72–/H+ (i.e. K2Cr2O7/H2SO4) to form carboxylic acids

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  2. b (i)

    nucleophilic addition reactions of carbonyl compounds with NaBH4 to form alcohols

    Revise
  3. b (ii)

    nucleophilic addition reactions of carbonyl compounds with HCN [i.e. NaCN(aq)/H+(aq)], to form hydroxynitriles (see also 6.2.4 b)

    Revise
  4. c i

    the mechanism for nucleophilic addition reactions of aldehydes and ketones with NaBH4

    Revise
  5. c ii

    the mechanism for nucleophilic addition reactions of aldehydes and ketones with HCN

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  6. d (i)

    use of 2,4-dinitrophenylhydrazine to detect the presence of a carbonyl group in an organic compound

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  7. d (ii)

    use of 2,4-dinitrophenylhydrazine to identify a carbonyl compound from the melting point of the derivative

    Revise
  8. e (i)

    use of Tollens' reagent (ammoniacal silver nitrate) to detect the presence of an aldehyde group

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  9. e (ii)

    use of Tollens' reagent (ammoniacal silver nitrate) to distinguish between aldehydes and ketones, explained in terms of the oxidation of aldehydes to carboxylic acids with reduction of silver ions to silver

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